1. Field of the Invention
This invention concerns gas lift operations, in general, and more specifically it deals with an improved structure for use in combination with a conventional gas lift valve and mandrel unit. It provides better protection against plugging of the gas lift valve port.
2. Description of the Prior Art
A conventional type of gas lift valve structure employs a mandrel with gas lift valve mounted thereon. The mandrel is a coupling member that is fastened into a tubing string at some desired location. The structure is such that the gas lift valve has a relatively small sized diameter, and is consequently only provided with a relatively small sized port for accomodating the gas flow when the valve opens. Since the gas which flows through such port is considerable in quantity and is under relatively high pressure, the tendency has been found great for the port to become plugged. Furthermore, even though the conventional arrangement has included a screen element adjacent to the valve port, it has failed to overcome the tendency to plug since the gas flow rate has remained very high and thus has tended to attract and cause to stick any foreign matter that would plug the screen and inactivate the valve.
Furthermore, while there have been some previous structures in connection with wells which dealt with the flow of fluids down hole, these have involved rather complex structures such that the resulting units are quite complex and therefore would be expensive.
Consequently, it is an object of this invention to provide an improved combination of elements that relates to a conventional gas lift valve which is used in combination with a mandrel for mounting the valve in place in a tubing string.